Hard disk drives essentially include at least one rotating data storage disk defining data storage surfaces. Typically, although not necessarily, each data surface defines a multiplicity of closely spaced apart data tracks. In some disk drives such as those employing optical data storage techniques, a spiral track arrangement is preferred. A read-write data transducer head is positioned by a track accessing mechanism, usually called an actuator, at each desired data storage location by moving the head radially across the storage surface. Usually heads are mounted by a single actuator arm structure, and all heads are radially positioned by a single positioning movement of the actuator. Small voice coil rotary actuators have come into vogue with the proliferation of smaller form factor disk drives, such as those of the 31/2 inch, 21/2 inch, and smaller storage disk diameters.
Rotary voice coil actuators typically include an "E-block" rotatably mounted by bearings to a post mounted to a base. A flat, multi-turn coil is typically attached to the E-block by a molding or potting compound, and the coil includes two radial side sections which cut through flux lines of opposed polarity present in a magnetic gap through which the coil is displaced as the actuator rotates through its range of limited angular displacement in positioning the head. Permanent magnets fixed to stationary magnet mounting plates typically provide the flux lines in the magnetic gap. When current is passed through the coil in one direction, the coil and E-block rotate in one direction. When current flow direction is reversed, the coil and E-block rotate in the opposite direction. Thus, by applying controlled currents to the coil, the actuator E-block will position the heads at the desired location, and maintain that position in overcoming bias forces otherwise tending to move the transducer off of the desired track location.
Of course, it is necessary to supply the electrical driving current to the actuator coil, and it is also necessary to provide electrical connections to each one of the data transducer heads, so that writing signals may be applied therethrough to the data tracks, and so that minute electrical signals transduced from the data tracks during reading may be conducted to preamplification circuitry.
Typically, connections to the rotary actuator have been made by providing a flexible circuit substrate typically formed of a thin polyimide film carrying conductive circuit traces. One example of a flexible circuit substrate is found in commonly assigned U.S. Pat. No. 4,669,004, as shown in FIGS. 1-3 thereof and identified by a reference numeral 42. A similar substrate, identified by a reference numeral 96, is shown in FIG. 1 of commonly assigned U.S. Pat. No. 5,005,089. A more extended discussion of a flex circuit said to apply zero bias force to the actuator is found in U.S. Pat. No. 4,933,785 beginning at e.g. column 8, lines 18-31, and at column 10, line 7, and continuing through column II, line 32. These prior patents are incorporated herein by way of background reference material, and are believed fairly representative the state of the art known to applicant's assignee.
One drawback of the prior art has been the electrical/mechanical interface between the flex circuit, and very fine conductor wires which extend from the moving end of the flex circuit to each data transducer head. These wires are typically contained in, and guided by a small diameter plastic wire tube which extends from adjacent the flex circuit to adjacent the data transducer head. The wire tube is typically routed along the head arm segment of the E-block and also routed along an edge of a head load beam. Commonly assigned U.S. Pat. No. 5,027,241 illustrates a preferred form of tube and load beam arrangement in FIG. 3 thereof, and this patent is hereby incorporated herein by reference.
Heretofore, it has been a common practice to provide additional mounting structure, or to glue or otherwise affix the plastic guide tubes to the end of the substrate. This arrangement has not always provided for a robust mechanical securement of the guide tubes to the flex circuit, and has required an additional gluing step during drive fabrication. Thus, a hitherto unsolved need has remained for a simplified, yet mechanically robust, mounting arrangement for securing the plastic head wire mounting tubes to the flex circuit.